Technical Field
The present invention relates to a circuit board structure and a manufacturing method thereof, more particularly, relates to a circuit board structure having a cavity and a manufacturing method thereof.
Background
Generally, in order to manufacture a circuit board structure having a cavity, a copper alignment layer is usually required to be formed on a core layer of an inner circuit structure for the following purpose. When laser ablates the circuit structure to form the cavity in the subsequent process, other than being regarded as a laser blocking layer to prevent the circuit structure from being excessively ablated, the copper alignment layer may also be regarded as a laser alignment pattern that is helpful in performing the laser ablation process. However, because the copper alignment layer is directly formed on the core layer of the inner circuit layer, a circuit layout of the core layer is restricted, and a wiring flexibility of the core layer is thus reduced.